The purpose of this project is to develop methods for gene transfer to mammalian cells and to use these techniques for gene mapping, analysis of gene expression, and cloning eukaryotic genes. Many independent somatic cell hybrid lines segrating human chromosomes have been isolated and the human chromosome content of each line determined. Analysis of these lines with isotopically labeled cloned DNA probes has previously allowed assignment to specific human chromosomes, and sometimes regional localization, of human cellular onc genes, immunoglobulin genes and pseudogenes, and Alpha, Beta, and Gamma fibrinogen genes. Similar procedures have been used to localize the metallothionein multigene family to chromosomes 1, 4, 16, 18, and 20 and the calcitonin gene to chromosome 11p. Chromosomal mapping of cytochrome p-450 genes and the O-methylguanine-DNA methyltransferase gene are in progress. Preliminary studies have failed to detect any rearrangement of cellular protoncogenes in guinea pig Leukemia. Transfection assays with this leukemia DNA fail to produce foci on NIH/3T3 monolayers. Other methods are being evaluated to detect transforming genes in the leukemic cells.